Table 3 Correlation (r value) of the candidate scores with items from the ISSAS database

	ASDAS A	ASDAS B	ASDAS C	ASDAS D
Included variables	BASDAI Q2 Patient global BASDAI Q6 Ln (CRP+1) √(ESR)	Patient global √(ESR) BASDAI Q3 BASDAI Q6 BASDAI Q2	BASDAI Q2 Patient global BASDAI Q3 BASDAI Q6 Ln (CRP+1)	√(ESR) BASDAI Q2 Ln (CRP+1) BASDAI Q6 BASDAI Q1

Excluded variables	–	CRP	ESR	Patient global

Items from ISSAS database
BASDAI	0.67	0.80	0.75	0.68
Patient global	0.72	0.76	0.75	0.63
BASFI	0.60	0.65	0.62	0.60
CRP	0.69	0.46	0.68	0.70
ESR	0.71	0.68	0.49	0.72
Swollen joint count	0.27	0.34	0.28	0.27

ASDAS, Ankylosing Spondylitis Disease Activity Score; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; ISSAS, International Study on Starting TNF blocking agents in Ankylosing Spondylitis; Q, question; TNF, tumour necrosis factor.